Flame structure of gas burner

ABSTRACT

A fire hole part structure of a gas burner, which is constructed to be manufactured at a low cost, can improve flame stability, and can prevent incomplete combustion due to the length of flame. The structure is provided to a premixing ignition burner, which is installed to apply heat to a heat exchanger of a boiler, and includes fire hole pieces which are installed parallel to one another in mounting openings of a burner body, and each of which is defined with fire holes at regular intervals. An upper wall of at least one of the fire hole pieces is bent or curved to extend in at least two directions, and the fire holes are defined through respective surface portions of the upper wall, which extend in different directions, to face different directions.

TECHNICAL FIELD

The present invention relates to a fire hole part structure of a gasburner, which can improve flame stability through impingement injectionof flame through fire holes and can reduce the generation of incompletecombustion products.

BACKGROUND ART

As a gas burner for a boiler or a water heating system, a Bunsen burnerwas used in the past, but a premixing ignition type burner is beingmainly used these days since it can reduce the generation of pollutantsand decrease the size of a combustion chamber.

The premixing ignition type burner has a fire hole part which hasdefined therein a plurality of fire holes for injecting the premixtureof fuel gas and air to thereby produce flame. A conventional fire holepart has a structure in which fire holes are defined through a singleplate member comprising a flat plate or a cylindrical plate. Theconventional fire hole part structure has problems in that thecombustion surface thereof is likely to be distorted or the shape of thefire holes is likely to be changed due to deformation by thermal stress,whereby incomplete combustion or backfiring can be caused.

In order to overcome these problems, a fire hole part structure, whichemploys a metal fiber mat formed by weaving metal fiber, or a ceramicplate formed by sintering ceramic, has been disclosed in the art.However, this structure incurs substantial material costs, and themanufacturing procedure is complicated, so that the manufacturing costsare increased. Also, because the configuration of a premixer is complex,pressure loss increases, the flame is unstable, and noise occurs.Further, the fire hole part structure suffers from defects due to thecharacteristics of the material thereof. For example, in the case of themetal fiber mat, since it has a certain degree of softness, thecombustion surface and fire holes are likely to be distorted due todeformation by the application of force upon assembly and due todrooping after installation. In the case of the sintered ceramic plate,as condensed water drips from the heat exchanger, arranged above theceramic plate, the fire hole part can be adversely affected.

FIG. 1 illustrates another conventional fire hole part structure for agas burner, which is formed at a reduced cost using a metal plate andcan solve the problems caused by deformation due to thermal stress.

In the illustrated conventional fire hole part, a plurality of fire holepieces 120 is installed in a parallel arrangement in mounting openings110 which are defined in the upper end of a burner body 100. Each firehole piece 120 is bent so as to define an elongate channel whichsubstantially has the sectional shape of a U rotated 180° so that itopens downward. A plurality of fire holes 121 is defined at regularintervals through the upper surface of each fire hole piece 120. Bothends of each fire hole piece 120 are fastened to the burner body 100 byfastening covers 123 and bolts.

Due to the fact that the fire hole part structure is constituted by thefire hole pieces 120, which are separately formed using metal plates,the manufacturing cost can be reduced. Further, since the respectiveseparate fire hole pieces 120 are individually fastened, deformation ofthe entire fire hole part due to thermal stress can be decreased. Also,by changing the number of fire hole pieces 120 for ease of mounting, theheating capacity of a burner can be easily adjusted.

DISCLOSURE OF INVENTION Technical Problem

However, the flame of a premixing ignition burner has narrow limits ofinflammability, unlike the diffusion flame of a Bunsen burner. In thecase of an ideal premixture combustion type flame, which is producedthrough the combustion of, for example, LNG, which contains methane as amain constituent thereof, flames are not produced at an excess airfactor of 1.6 or greater. In actual fact, since fuel and air are notideally mixed in the premixing ignition burner, flame can be producedeven at an excess air factor of 1.7, but in this case, the flame liftsoff the burner and becomes unstable.

Therefore, in the conventional fire hole part structure of a gas burner,in which flame is produced through the fire holes 121 defined on theflat upper surfaces of the fire hole pieces 120, since flame stabilizingmeans is not provided, the flame is likely to be unstable due tolifting. Also, as the load of the premixture, such as the flow amount orthe flow rate, is increased, the length of the flame is also increased,and the flame is likely to come into direct contact with the heatexchanger arranged above the burner. In this case, as the temperature ofthe flame decreases, incomplete combustion can occur, generating asubstantial amount of pollutants such as carbon monoxide, etc.

Technical Solution

Accordingly, an object of the present invention is to provide a firehole part structure of a gas burner, which is constructed to bemanufactured at a low cost, can improve flame stability, and can preventincomplete combustion attributable to the length of flame.

Advantageous Effects

Thanks to the features of the present invention, due to the fact thatimpingement injection of flame between adjoining fire hole pieces ismade possible through the fire holes, which are defined in at least twodirections inclined relative to a vertical direction, a flame holdingcharacteristic can be improved, and excellent flame stability can bemaintained even in combustion under a high load. Also, because thevertical length of the flame is decreased, incomplete combustion due tocontact between the heat exchanger and flame can be prevented, the sizeof the burner can be reduced, and the combustion load can be increased.

Moreover, by changing the shape or the arrangement of the fire holepieces depending upon the desired performance or conditions, it ispossible to provide a burner which can accomplish or further improve theabove-described effects.

Furthermore, by increasing the deformation strength of the fire holepiece through bending or curving the upper wall of the fire hole piece,even when a fire hole part is constructed such that the fire hole piecesare integrally connected with one another to constitute a single plate,deformation due to thermal stress can be reduced, and it is possible toprovide a fire hole part structure having improved durability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a conventional fire hole partstructure of a gas burner;

FIG. 2 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a first embodiment of the presentinvention;

FIG. 3 is cross-sectional view illustrating the main portion of the firehole part structure shown in FIG. 2;

FIG. 4 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a second embodiment of the presentinvention;

FIG. 5 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a third embodiment of the presentinvention;

FIG. 6 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a fourth embodiment of the presentinvention;

FIG. 7 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a fifth embodiment of the presentinvention;

FIG. 8 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a sixth embodiment of the presentinvention; and

FIG. 9 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a seventh embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

According to the present invention, there is provided a fire hole partstructure provided to a premixing ignition burner which is installed toapply heat to the heat exchanger of a boiler, and including a pluralityof fire hole pieces which are installed parallel to one another inmounting openings of a burner body and each of which is defined with anumber of fire holes at regular intervals, wherein an upper wall of atleast one of the fire hole pieces is bent or curved to extend in atleast two directions, and the fire holes are defined through respectivesurface portions of the upper wall, which extend in differentdirections, to face different directions.

MODE FOR THE INVENTION

The above objects, and other features and advantages of the presentinvention will become more apparent after a reading of the followingdetailed description. Hereafter, a preferred embodiment of the presentinvention will be described with reference to the attached drawings.

FIG. 2 is a perspective view illustrating a fire hole part structure ofa gas burner in accordance with a first embodiment of the presentinvention, and FIG. 3 is cross-sectional view illustrating the mainportion of the fire hole part structure shown in FIG. 2.

Referring to FIGS. 2 and 3, in a fire hole part structure for a gasburner in accordance with a first embodiment of the present invention,fire hole pieces 20 are installed parallel to and adjacent to oneanother in a plurality of mounting openings 13 which are defined in theupper portion of a burner body 11.

The burner body 11 is a conventional one. While not shown in thedrawings, a manifold, in which fuel gas and air are mixed with eachother, is coupled to the lower portion of the burner body 11. A gassupply pipe for supplying fuel and a blower for supplying air arecoupled to the manifold. Since the burner body 11 has a conventionalconfiguration, detailed description thereof will be omitted herein.

A plurality of premixture accommodating spaces 14, which are separatedby partition walls 12, is defined in the burner body 11 according to thecapacity of the gas burner. Each premixture accommodating space 14 isopened upward, and the upper end thereof defines the mounting opening13.

Each fire hole piece 20 has an upper wall 21 which is bent along thecenter portion thereof in the lengthwise direction thereof, and definesa channel which is opened downward. The upper wall 21 is bent to have awedge-shaped section which projects upward. The plurality of fire holes23 is defined through surface portions which are divided by a bendingline 24 in a manner such that the discharge directions of premixturethrough the fire holes 23 are inclined with respect to the verticaldirection. Preferably, the fire holes 23 defined in both sides of thebending line 24 are arranged to be staggered with each other.

Fastening holes 16 are defined in the burner body 11 adjacent to bothlengthwise ends of the mounting openings 13. Support lips 27 to bereceived in the fastening holes 16 are formed on both lengthwise ends ofthe fire hole pieces 20. As fastening plates 15 are locked to the burnerbody 11 by bolts 17 in such a way as to press the support lips 27, thefire hole pieces 20 are fastened to the burner body 11. A plurality ofgrooves 25 is defined in the sidewalls of the fire hole pieces 20 toprevent distortion of the fire hole pieces 20 due to thermal stress andto promote cooling of the fire hole pieces 20.

As described above, in the fire hole part structure according to thepresent invention, the upper wall 21 of each fire hole piece 20 is bentsuch that two inclined surface portions extending in differentdirections are formed, and the fire holes 23 are defined through the twoinclined surface portions. Therefore, as shown in FIG. 3, the injectiondirection of the flame created through each fire hole 23 is inclinedwith respect to the vertical direction, and the two flames injectedthrough the two facing fire holes 23 of adjoining fire hole pieces 20interfere with each other, by which flame stabilizing means is formed.

Accordingly, in the case of the fire hole pieces 20 according to thepresent invention, flame stability is improved compared to theconventional fire hole pieces formed of flat plates. Therefore, evenwhen the air ratio of the flame or the load of a premixer is increased,flame lifting and resultant flame instability do not occur. Also, sincethe vertical length of the flame is shortened, the generation ofincomplete combustion products, such as carbon monoxide, etc., which maybe caused when the flame comes into direct contact with a heatexchanger, can be avoided. As a consequence, by adopting the fire holepart structure according to the present invention, the height of thecombustion chamber of the burner can be decreased, and the thermal loadper unit area can be increased, whereby high load combustion can beeffected using a burner structure having a reduced size. Moreover,assuming that the width of the fire hole piece 20 and the intervalbetween the fire holes 23 are the same, the length of the fire hole 23is decreased by about half, and the number of fire holes 23 is doubled,whereby the above-described effects can be further improved.

Moreover, due to the fact that the surface portions of the fire holepiece 20, which are bent along the bending line 24, are located atstaggered positions, even when the fire holes 23 are densely definedthrough the fire hole pieces 20 to thus have a narrow interval, theflames created through adjoining fire holes 23 do not needlesslyinterfere or combine with each other. Therefore, it is possible torealize a burner structure which permits high load combustion and thecombustion intensity of which can be adjusted. Also, for the samereason, while not shown in the drawings, it is possible for the facingfire holes 23 of two adjoining fire hole pieces 20 to be defined to bestaggered with respect to each other.

Meanwhile, although, in this embodiment, the fire hole piece 20 wasillustrated as being bent to have a wedge-shaped section that projectsupward, it is to be readily understood that the present invention is notlimited to this concrete example. Therefore, the upper wall 21 of thefire hole piece 20 can be bent or curved to have various sections sothat the fire holes 23 defined through the fire hole pieces 20 face atleast two different directions. For example, as shown in FIG. 8, theupper wall 21 of the fire hole piece 20 can be bent downward toward theinside of the burner body 11 in a manner such that the upper surface ofeach fire hole piece 20 has a wedge-shaped section, similar to theabove-described embodiment, but the bending line 24 is depresseddownward, unlike the above-described embodiment.

Also, in addition to the wedge-shaped section, as shown in FIG. 4, theupper wall 21 of each fire hole piece 20 can be curved upward in amanner such that the upper surface of each fire hole piece 20 has anarc-shaped section. The plurality of fire holes 23 is defined at two ormore positions on the upper surface thereof to face directions which areinclined with respect to the vertical direction. Even in this sectionalshape, similar to the wedge-shaped section described just above, theupper wall 21 can be curved downward toward the inside of the burnerhousing 11, as shown in FIG. 9.

As the case may be, the fire hole pieces 20 may not have the samesectional shape. For example, as shown in FIG. 5, fire hole pieces 20 aeach having a flat upper surface, similar to the conventional fire holepiece 120 and three-dimensional fire hole pieces 20, each having anupper wall 21 which is bent or curved, as described above, can bealternately arranged with each other. That is to say, differently shapedfire hole pieces 20 and 20 a can be alternately arranged with eachother. In the case where the fire hole pieces 20 and 20 a are arrangedas shown in FIG. 5, since both side portions of the flame, which iscreated through the flat type fire hole piece 20 a, interfere with theflames which are created through two adjoining three-dimensional firehole pieces 20, the flame holding characteristic and flame stability, asdescribed above, can be improved, and impingement angle and the intervalof flame can be easily adjusted within a wide range.

Further, as shown in FIG. 5, in the case of the fire hole pieces 20 bwhich are positioned on both side ends of the burner body 11, in orderto avoid flame instability and incomplete combustion, which may occurdue to direct contact of the flame with the burner body 11, it ispreferred that only one surface portion of the two surface portions ofthe fire hole piece 20 b which faces adjacent fire hole piece 20 or 20 abe defined with the fire holes 23, and that the other surface portion ofthe two surface portions of the fire hole piece 20 b, which faces thewall of the burner body 11, not be defined with the fire holes 23.

In another embodiment of the fire hole pieces 20, which are positionedon both side ends of the burner body 11, as shown in FIG. 6, each firehole piece 20 can be configured in a manner such that the surfaceportion, which faces the center of the fire hole part, is formed as aninclined surface 28, the surface portion, which faces away from thecenter of the fire hole part, is formed as a vertical surface 29 to bebrought into contact with the wall of the burner body 11, and the fireholes 23 are defined only through the inclined surface 28.

Further, although it was illustrated in the above-described embodimentsthat the respective fire hole pieces 20 are formed of individuallyseparated plate members, as the case may be, as shown in FIG. 7, asingle plate member can be bent so that the plurality of fire holepieces 20 can be integrally connected with one another. Even in thiscase, since the upper surfaces 21 of the respective fire hole pieces 20are bent or curved, the deformation strength of the fire hole partstructure can be improved. Also, because a plurality of grooves 25 isdefined in the sidewalls of the integrated fire hole pieces 20 todisperse thermal stress, even though the respective fire hole pieces 20are not separated from one another, deformation due to thermal stress isdecreased compared to the conventional fire hole part structure formedof the flat plates.

INDUSTRIAL APPLICABILITY

The present invention can provide a fire hole part structure of a gasburner, which is constructed to be manufactured at low cost, can improveflame stability, and can prevent incomplete combustion due to the lengthof a flame.

1. A fire hole part structure comprising: a plurality of fire holepieces configured to be installed parallel to one another in at leastone mounting opening of a burner body, and wherein each fire hole piecehas defined therein a plurality of fire holes at regular intervals,wherein an upper wall of at least a first fire hole piece is configuredwith two surface portions, wherein each of the two surface portionsfaces a different direction, and wherein each of the two surfaceportions includes at least two fire holes.
 2. The fire hole partstructure according to claim 1, wherein the upper wall of the first firehole piece has a wedge-shaped or an arc-shaped section which is one of,concave or convex.
 3. The fire hole part structure according to claim 1,wherein the plurality of fire hole pieces are installed in the burnerbody, and wherein the fire hole pieces which are installed in outermostregions of the burner body contain fire holes only on surface portionsof the upper walls that face towards adjoining fire hole pieces.
 4. Thefire hole part structure according to claim 1, wherein the fire holesdefined through the two surface portions of the upper wall of each firehole piece are staggered relative to each other.
 5. The fire hole partstructure according to claim 1, wherein the plurality of fire holepieces are formed by bending a single plate so that the fire hole piecesare integrally connected with one another.
 6. The fire hole partstructure according to claim 2, wherein, the plurality of fire holepieces are installed in the burner body, and wherein the fire holepieces which are installed in outermost regions of the burner bodycontain fire holes only on surface portions of the upper walls that facetowards adjoining fire hole pieces.
 7. The fire hole part structureaccording to claim 2, wherein the fire holes defined through the twosurface portions of the upper wall of each fire hole piece are staggeredrelative to each other.
 8. The fire hole part structure according toclaim 2, wherein the plurality of fire hole pieces are formed by bendinga single plate so that the fire hole pieces are integrally connectedwith one another.
 9. The fire hole part structure according to claim 1,wherein the fire hole structure is provided to a premixing ignitionburner which is installed to apply heat to a heat exchanger of a boiler.